16 amp supply

[RorieT]

Hi folks,

Just joined in the hope someone can help! - don't worry, i'll get a sparky in to do the work, but i want to understand whats needed first!

I have purchased a new workshop table saw which came with a 16 amp socket, though i was advised it would work fine off a 13amp socket with a plug converter.

The saw has a NVR switch. Sometimes it starts first time, but especially after running a couple of times, i need to hold the NVR on until the motor gets up to speed, otherwise the saw cuts out (but never blows the fuse)

I called the saw manufacturer who advised the problem is because there is not enough 'supply' and that i need to install a 16amp socket running off a 16 amp 'c' breaker. He seemed bang on certain that this was the problem

So

1) Does that sound right? could the 13 amp ring main (even with no other load) be restricting the supply?
2) I have a Schneider RCD consumer unit which has 'b6' and 'b32' breakers in just now. How do i know if i can add / change these out for 'c' type? Or does the whole unit need changed for an industrial unit?
3) when running a cable for a 16amp socket, what is the advised cable size? I have been advised that 2.5 T&E is acceptable for up to 20amp.

Thanks!
[h=1][/h]

 

[Richard Burns]

The saw manufacturer is incorrect , the supply would likely be capable of hundreds of amps (albeit damaging cables and blowing fuses) and there is no supply restriction, changing the breaker will have no effect of the "available" supply.
A C type MCB would be advisable for an item such as a table saw, however testing of the circuit and incoming supply would be necessary to ensure the circuit would be safe to do this with.

The likely possibility is that there may be a high resistance joint (loose connection) somewhere that is causing a voltage drop as the motor gets up to speed.
There will almost always be a voltage dip as the motor starts as it will be pulling a high load.
A larger cable and no loose connections would go some way to alleviate this effect.

 

[telectrix]

as above ^^^^^. a separate 20A circuit direct from CU is advisable here.

 

[RorieT]

Thanks for the replies folks.

Is the high resistance drop likely to be in the table saw its self, or something with the garage electrics?

What sort of thickness of cable would be advisable here? Its currently on 2.5mm t&E

And is it likely that i will need a new CU to fit a type 'c' breaker, or can this be added into most?

 

[Octopus]

Thanks for the replies folks.

Is the high resistance drop likely to be in the table saw its self, or something with the garage electrics?

What sort of thickness of cable would be advisable here? Its currently on 2.5mm t&E

And is it likely that i will need a new CU to fit a type 'c' breaker, or can this be added into most?

This would depend on the CU you have. Best to find a local spark to give you the direction you need......

 

[PEG]

...I was hoping to see a "Oh,and by the way,the garage is 400 meters from my house..." type of additional comment...just to cheer me up

To the OP.your saw should work fine,to test,using an adapter to a plug top,with no load.

If not,you will need to have some further testing done,starting with the normal supply characteristics,and maybe the motor itself,CS or capacitors etc

I have a pal,who has the same issue,in his barn,with an ancient table saw,he uses for chopping firewood.

He says it works fine,and the NVR "only drops out with oak,or that skinny extension lead..."

 

[RorieT]

Thanks for the replies.

I called the manufacturer again for some more info.... they are standing by the comment of not getting enough power and wont explore other options until i get a 16 amp supply in....

I also checked with my CU and its ok for a type 'c'. So i will add a type 'c' MCB 16amp to my CU and run a single 2.5mm T&E to a 16amp socket. The distance is only around 5m from the CB. Hopefully this will resolve the issue!

Oh, and as for testing under no-load.... when the saw is loaded it is fine - its only starting the saw (under no load) which seems to be the issue!

Thanks for the help!

 

[Deleted member 9648]

Thanks for the replies.

I called the manufacturer again for some more info.... they are standing by the comment of not getting enough power and wont explore other options until i get a 16 amp supply in....

I also checked with my CU and its ok for a type 'c'. So i will add a type 'c' MCB 16amp to my CU and run a single 2.5mm T&E to a 16amp socket. The distance is only around 5m from the CB. Hopefully this will resolve the issue!

Oh, and as for testing under no-load.... when the saw is loaded it is fine - its only starting the saw (under no load) which seems to be the issue!

Thanks for the help!

Unfortunately it is not as simple as just swapping for a type c. By doing so without carrying out a Zs test your circuit may not comply with the required disconnection time.

 

[RorieT]

Hi,
I am just buying the bits and bobs for installing the 16 amp supply. I was told to buy a "interlocking isolator socket" as this is required locally. I am wondering what exactly i need?

I have found THIS, but as i already have THIS, so wondering if i can add one of these instead?

I was looking at these more standard looking switches, but they all seem to be for 450v supplies….

Can anybody clarify what i need please?

Thanks!

 

[Octopus]

Hi,
I am just buying the bits and bobs for installing the 16 amp supply. I was told to buy a "interlocking isolator socket" as this is required locally. I am wondering what exactly i need?

I have found THIS, but as i already have THIS, so wondering if i can add one of these instead?

I was looking at these more standard looking switches, but they all seem to be for 450v supplies….

Can anybody clarify what i need please?

Thanks!

By whom?

 

[telectrix]

your last link isolator can be used for both 415 3 phase using all 4 poles, or for 240V single phase using 2 poles. your electrician will advise on the best solution, as has been said in previous posts.

 

[RorieT]

By whom?

The electrician - i want to source the materials myself and have everything mounted up to save time / cost. He'll just hook everything up and run the checks.

 

[Octopus]

The electrician - i want to source the materials myself and have everything mounted up to save time / cost. He'll just hook everything up and run the checks.

hum...then I recommend you email this "electrician" and ask him for a detailed list of parts.....

 

[RorieT]

your last link isolator can be used for both 415 3 phase using all 4 poles, or for 240V single phase using 2 poles. your electrician will advise on the best solution, as has been said in previous posts.

Thanks for the help. Looks like that'll be the one i need.

Murdoch: the electrician is on holiday just now which is why i was looking for an answer on here. Had there been no electrician, i would have said that! But thanks for providing no help in your last two comments - a typical forum warrier!